This is the last book in the 39 Clues series and it is a little different than the rest of the books. This book provides some family history on Gideon Cahill (1507) and his family and how the secret serum was developed. The book introduces Damien Vesper, the person who wants to get his hands on the formula for the serum in order to be the most powerful man in the world.
The history of the Madrigals is provided and the reader finds out about Gideon’s last daughter, Madeleine Cahill (1526). Madeleine becomes the keeper of Gideon’s ring, which has some strange writing on it that no one seems to know its meaning. The book presents Grace Cahill’s story (1942) and how she assumed responsibility for the family affairs.
If the reader has read the previous books, he will know that Grace Cahill is Amy and Dan’s grandmother. Her last wish is for Amy to be the keeper of the ring and keep it out of the hands of the Vespers. This doesn’t prove easy when she and Dan are attacked in Switzerland. Amy comes up with an ingenious way to hide the ring. She and Dan realize that in order to keep the Cahill legacy safe, there is a lot they need to learn. This takes the reader to the next series about Amy’s and Dan’s adventures with the Vespers.
I highly recommend this book for Middle Readers and Older Readers. I like that the authors provide family history, so the reader understands how the Cahill family divided itself and why someone is after the formula and the ring. I look forward to reading the next series.
Reviewed by Karen Limbaugh, Librarian (Retired), Texas, USA